This invention relates to a process for the recovery of copper chlorides from aqueous solutions and, more particularly, relates to a process for the recovery of cuprous chloride from hydrometallurgical process solutions by extraction with unsaturated hydrocarbons.
In hydrometallurgical processes for the treatment of copper bearing materials employing chloride lixivium, cuprous chloride is a preferred intermediate compound because of the monovalent state of the copper. Moreover, the physical properties of the cuprous chloride make separation of copper from most other metals possible. The various known methods for obtaining cuprous chloride by hydrometallurgical processes, such as by crystallization, however, permit relatively low yields of cuprous chloride and are comparatively uneconomical.
It is well known that certain unsaturated hydrocarbons form addition compounds with compounds of metals such as copper, silver, mercury, platinum and palladium. In the petroleum processing industry this has been applied to the extraction of unsaturated hydrocarbons, particularly olefins and diolefins, from hydrocarbon mixtures.
In U.S. Pat. No. 1,795,549, which issued on Mar. 10, 1931, there is disclosed a process for the recovery of diolefins with conjugated double carbon bonds from gaseous mixtures by treating such mixtures with a heavy-metal salt and liberating the diolefins from the resulting addition compounds.
In German Pat. No. 611,460, which issued on Mar. 28, 1935, there is disclosed a process for the recovery of acetylene wherein copper is added to an acidic solution of cupric chloride, the resulting solution is treated with acetylene and the formed addition compound is decomposed at a temperature from 50.degree. to 60.degree. C. and/or under reduced pressure to recover the acetylene.
In U.S. Pat. No. 2,375,576, which issued on May 8, 1945, there is disclosed a process for concentrating and separating butadiene by passing a hydrocarbon liquid containing the diolefin in countercurrent flow with a cuprous salt solution and separating butadiene from separated cuprous salt solution by heating.
The prior art, however, does not disclose the extraction of copper chlorides from aqueous solutions encountered in hydrometallurgical processes for the recovery of copper from copper bearing materials by treating such solutions with unsaturated hydrocarbons.